Cost-Effectiveness of CT, CTA, MRI, and Specialized MRI for Evaluation of Patients Presenting to the Emergency Department With Dizziness

BACKGROUND. Underlying stroke is often misdiagnosed in patients presenting with dizziness. Although such patients are usually ineligible for acute stroke treatment, accurate diagnosis may still improve outcomes through selection of patients for secondary prevention measures. OBJECTIVE. The purpose of our study was to investigate the cost-effectiveness of differing neuroimaging approaches in the evaluation of patients presenting to the emergency department (ED) with dizziness who are not candidates for acute intervention. METHODS. A Markov decision-analytic model was constructed from a health care system perspective for the evaluation of a patient presenting to the ED with dizziness. Four diagnostic strategies were compared: noncontrast head CT, head and neck CTA, conventional brain MRI, and specialized brain MRI (including multiplanar high-resolution DWI). Differing long-term costs and outcomes related to stroke detection and secondary prevention measures were compared. Cost-effectiveness was calculated in terms of lifetime expenditures in 2022 U.S. dollars for each quality-adjusted life year (QALY); deterministic and probabilistic sensitivity analyses were performed. RESULTS. Specialized MRI resulted in the highest QALYs and was the most cost-effective strategy with US$13,477 greater cost and 0.48 greater QALYs compared with noncontrast head CT. Conventional MRI had the next-highest health benefit, although was dominated by extension with incremental cost of US$6757 and 0.25 QALY; CTA was also dominated by extension, with incremental cost of US$3952 for 0.13 QALY. Non-contrast CT alone had the lowest utility among the four imaging choices. In the deterministic sensitivity analyses, specialized MRI remained the most cost-effective strategy. Conventional MRI was more cost-effective than CTA across a wide range of model parameters, with incremental cost-effectiveness remaining less than US$30,000/QALY. Probabilistic sensitivity analysis yielded similar results as found in the base-case analysis, with specialized MRI being more cost-effective than conventional MRI, which in turn was more cost-effective than CTA. CONCLUSION. The use of MRI in patients presenting to the ED with dizziness improves stroke detection and selection for subsequent preventive measures. MRI-based evaluation leads to lower long-term costs and higher cumulative QALYs. CLINICAL IMPACT. MRI, incorporating specialized protocols when available, is the preferred approach for evaluation of patients presenting to the ED with dizziness, to establish a stroke diagnosis and to select patients for secondary prevention measures.

Altered parietal operculum cortex 2 functional connectivity in benign paroxysmal positional vertigo patients with residual dizziness: A resting-state fMRI study

AIMS

To investigate changes in functional connectivity (FC) focusing on parietal operculum cortex 2 (OP2) in benign paroxysmal positional vertigo (BPPV) patients with residual dizziness (RD) after successful canalith repositioning procedure (CRP).

METHODS

High-resolution three-dimensional T1 and resting-state functional magnetic resonance imaging (fMRI) were performed on 55 healthy controls (HCs), 55 BPPV patients with RD, and 55 patients without RD after successful CRP. Seed-based (bilateral OP2) FC was calculated to investigate the changes in FC among the three groups. Additionally, we further explored the associations between abnormal FC and clinical symptoms.

RESULTS

One-way analysis of covariance showed significant FC differences among the three groups. Post-hoc analysis showed that patients with RD exhibited decreased FC between left OP2 and regions of left angular gyrus (AG), thalamus, precuneus, middle frontal gyrus (MFG), and right cerebellum posterior lobe (CPL) in comparison with HCs. In addition, compared with patients without RD, patients with RD showed decreased FC between left OP2 and regions of left MFG, AG, middle temporal gyrus, and right CPL. Moreover, in patients with RD, the FC between left thalamus and OP2 was negatively correlated with duration of RD, and the FC between left AG and OP2 was negatively correlated with duration of BPPV.

CONCLUSION

BPPV patients with RD showed reduced FC between brain regions involved in vestibular processing and spatial cognition; These results suggested that BPPV patients with RD might have diminished central processing of vestibular information and impaired spatial cognition.

CT With CTA Versus MRI in Patients Presenting to the Emergency Department With Dizziness: Analysis Using Propensity Score Matching

BACKGROUND. CT with CTA is widely used to exclude stroke in patients with dizziness, although MRI has higher sensitivity. OBJECTIVE. The purpose of this article was to compare patients presenting to the emergency department (ED) with dizziness who undergo CT with CTA alone versus those who undergo MRI in terms of stroke-related management and outcomes. METHODS. This retrospective study included 1917 patients (mean age, 59.5 years; 776 men, 1141 women) presenting to the ED with dizziness from January 1, 2018, to December 31, 2021. A first propensity score matching analysis incorporated demographic characteristics, medical history, findings from the review of systems, physical examination findings, and symptoms to construct matched groups of patients discharged from the ED after undergoing head CT with head and neck CTA alone and patients who underwent brain MRI (with or without CT and CTA). Outcomes were compared. A second analysis compared matched patients discharged after CT with CTA alone and patients who underwent specialized abbreviated MRI using multiplanar high-resolution DWI for increased sensitivity for posterior circulation stroke. Sensitivity analyses were performed involving MRI examinations performed as the first or only neuroimaging examination and involving alternative matching and imputation techniques. RESULTS. In the first analysis (406 patients per group), patients who underwent MRI, compared with patients who underwent CT with CTA alone, showed greater frequency of critical neuroimaging results (10.1% vs 4.7%, p = .005), change in secondary stroke prevention medication (9.6% vs 3.2%, p = .001), and subsequent echocardiography evaluation (6.4% vs 1.0%, p < .001). In the second analysis (100 patients per group), patients who underwent specialized abbreviated MRI, compared with patients who underwent CT with CTA alone, showed greater frequency of critical neuroimaging results (10.0% vs 2.0%, p = .04), change in secondary stroke prevention medication (14.0% vs 1.0%, p = .001), and subsequent echocardiography evaluation (12.0% vs 2.0%, p = .01) and lower frequency of 90-day ED readmissions (12.0% vs 28.0%, p = .008). Sensitivity analyses showed qualitatively similar findings. CONCLUSION. A proportion of patients discharged after CT with CTA alone may have benefitted from alternative or additional evaluation by MRI (including MRI using a specialized abbreviated protocol). CLINICAL IMPACT. Use of MRI may motivate clinically impactful management changes in patients presenting with dizziness.

Clinical criteria to exclude acute vascular pathology on CT angiogram in patients with dizziness

BACKGROUND

Patients presenting to the emergency department (ED) with dizziness may be imaged via CTA head and neck to detect acute vascular pathology including large vessel occlusion. We identify commonly documented clinical variables which could delineate dizzy patients with near zero risk of acute vascular abnormality on CTA.

METHODS

We performed a cross-sectional analysis of adult ED encounters with chief complaint of dizziness and CTA head and neck imaging at three EDs between 1/1/2014-12/31/2017. A decision rule was derived to exclude acute vascular pathology tested on a separate validation cohort; sensitivity analysis was performed using dizzy "stroke code" presentations.

RESULTS

Testing, validation, and sensitivity analysis cohorts were composed of 1072, 357, and 81 cases with 41, 6, and 12 instances of acute vascular pathology respectively. The decision rule had the following features: no past medical history of stroke, arterial dissection, or transient ischemic attack (including unexplained aphasia, incoordination, or ataxia); no history of coronary artery disease, diabetes, migraines, current/long-term smoker, and current/long-term anti-coagulation or anti-platelet medication use. In the derivation phase, the rule had a sensitivity of 100% (95% CI: 0.91-1.00), specificity of 59% (95% CI: 0.56-0.62), and negative predictive value of 100% (95% CI: 0.99-1.00). In the validation phase, the rule had a sensitivity of 100% (95% CI: 0.61-1.00), specificity of 53% (95% CI: 0.48-0.58), and negative predictive value of 100% (95% CI: 0.98-1.00). The rule performed similarly on dizzy stroke codes and was more sensitive/predictive than all NIHSS cut-offs. CTAs for dizziness might be avoidable in 52% (95% CI: 0.47-0.57) of cases.

CONCLUSIONS

A collection of clinical factors may be able to "exclude" acute vascular pathology in up to half of patients imaged by CTA for dizziness. These findings require further development and prospective validation, though could improve the evaluation of dizzy patients in the ED.

Retrospective Analysis of the Association of a Small Vestibular Aqueduct with Cochleovestibular Symptoms in a Large, Single-Center Cohort Undergoing CT

BACKGROUND AND PURPOSE

Temporal bones in some patients with Ménière disease have demonstrated small vestibular aqueducts; however, the prevalence and clinical importance of small vestibular aqueducts remain unclear in patients without Ménière disease. This study correlates the presence of a small vestibular aqueduct with cochleovestibular symptoms.

MATERIALS AND METHODS

Consecutive temporal bone CTs in adults from January to December 2020 were reviewed. The midpoint vestibular aqueduct size in the 45°-oblique Pöschl view was measured by 2 reviewers independently in 684 patients (1346 ears). Retrospective chart review for the clinical diagnosis of Ménière disease, the presence of cochleovestibular symptoms, and indications for CT was performed.

RESULTS

Fifty-two of 684 patients (7.6% of patients, 62/1346 ears) had small vestibular aqueducts. Twelve patients (15/1346 ears) had Ménière disease. Five of 12 patients with Ménière disease (5 ears) had a small vestibular aqueduct. There was a significant correlation between a small vestibular aqueduct and Ménière disease (P < .001). There was no statistical difference between the small vestibular aqueduct cohort and the cohort with normal vestibular aqueducts (0.3-0.7 mm) regarding tinnitus (P = .06), hearing loss (P = .88), vertigo (P = .26), dizziness (P = .83), and aural fullness (P = .61).

CONCLUSIONS

While patients with Ménière disease were proportionately more likely to have a small vestibular aqueduct than patients without Ménière disease, the small vestibular aqueduct was more frequently seen in patients without Ménière disease and had no correlation with hearing loss, vertigo, dizziness, or aural fullness. We suggest that the finding of a small vestibular aqueduct on CT could be reported by radiologists as a possible finding in Ménière disease, but it remains of uncertain, and potentially unlikely, clinical importance in the absence of symptoms of Ménière disease.

Neurofunctional differences and similarities between persistent postural-perceptual dizziness and anxiety disorder

INTRODUCTION

Persistent postural-perceptual dizziness (PPPD) (ICD-11) and anxiety disorders (ANX) share behavioural symptoms like anxiety, avoidance, social withdrawal, hyperarousal, or palpitation as well as neurological symptoms like vertigo, stance and gait disorders. Furthermore, previous studies have shown a bidirectional link between vestibulo-spatial and anxiety neural networks. So far, there have been no neuroimaging-studies comparing these groups.

OBJECTIVES

The aim of this explorative study was to investigate differences and similarities of neural correlates between these two patient groups and to compare their findings with a healthy control group.

METHODS

63 participants, divided in two patient groups (ANX = 20 and PPPD = 14) and two sex and age matched healthy control groups (HC-A = 16, HC-P = 13) were included. Anxiety and dizziness related pictures were shown during fMRI-measurements in a block-design in order to induce emotional responses. All subjects filled in questionnaires regarding vertigo (VSS, VHQ), anxiety (STAI), depression (BDI-II), alexithymia (TAS), and illness-perception (IPQ). After modelling the BOLD response with a standard canonical HRF, voxel-wise t-tests between conditions (emotional-negative vs neutral stimuli) were used to generate statistical contrast maps and identify relevant brain areas (pFDR < 0.05, cluster size >30 voxels). ROI-analyses were performed for amygdala, cingulate gyrus, hippocampus, inferior frontal gyrus, insula, supramarginal gyrus and thalamus (p ≤ 0.05).

RESULTS

Patient groups differed from both HC groups regarding anxiety, dizziness, depression and alexithymia scores; ratings of the PPPD group and the ANX group did differ significantly only in the VSS subscale 'vertigo and related symptoms' (VSS-VER). The PPPD group showed increased neural responses in the vestibulo-spatial network, especially in the supramarginal gyrus (SMG), and superior temporal gyrus (STG), compared to ANX and HC-P group. The PPPD group showed increased neural responses compared to the HC-P group in the anxiety network including amygdala, insula, lentiform gyrus, hippocampus, inferior frontal gyrus (IFG) and brainstem. Neuronal responses were enhanced in visual structures, e.g. fusiform gyrus, middle occipital gyrus, and in the medial orbitofrontal cortex (mOFC) in healthy controls compared to patients with ANX and PPPD, and in the ANX group compared to the PPPD group.

CONCLUSIONS

These findings indicate that neuronal responses to emotional information in the PPPD and the ANX group are comparable in anxiety networks but not in vestibulo-spatial networks. Patients with PPPD revealed a stronger neuronal response especially in SMG and STG compared to the ANX and the HC group. These results might suggest higher sensitivity and poorer adaptation processes in the PPPD group to anxiety and dizziness related pictures. Stronger activation in visual processing areas in HC subjects might be due to less emotional and more visual processing strategies.

Pilot MRI-based strategies to improve the detection of stroke in patients with dizziness/vertigo

Posterior strokes are frequently misdiagnosed as they present with non-specific complaints such as dizziness/vertigo. Emergency department (ED) practice often relies on CT/CTA to "exclude" infarct in such patients, providing false reassurance due to lower sensitivity of CT (42%) for stroke in the posterior circulation. We describe a pilot at our institution using a specialized MRI protocol with 95% sensitivity for posterior stroke, which may be used in place of CT/CTA or conventional MRI for stroke evaluation. Further development of this approach may help reduce the high rate of missed posterior stroke in patients presenting with dizziness.

A comparison of benign positional vertigo and stroke patients presenting to the emergency department with vertigo or dizziness

PURPOSE

To compare imaging utilization between patients presenting to the emergency department (ED) with vertigo and dizziness (VDS) who are diagnosed with stroke and benign paroxysmal positional vertigo (BPPV).

METHODS

All patients presenting to the ED with VDS (January 2014-June 2018) were identified. Those with a discharge diagnosis of stroke and BPPV were analyzed.

RESULTS

17,884 patients presented to with VDS. 452 were diagnosed with BPPV and 174 with acute stroke. 55.7% of stroke patients had at least one neurologic symptom beyond VDS, 63.8% had a positive neurologic exam, and 80.5% had either; 90.2% had at least one stroke risk factor (RF). 42.0% of BPPV patients received imaging, of which 24.7% had neurologic symptoms beyond VDS, 16.3% had neurologic exam findings, and 34.2% had either (P < 0.001, as compared to stroke). 43 patients (22.6%) lacked neurologic symptoms, exam findings, and stroke RFs; 40 had an adequate HINTS (head impulse, nystagmus, skew) exam. The most common imaging modality received by BPPV patients was plain CT Head (54.2%), followed by CT/CTA (43.7%), and MRI brain (26.3%). CT head was the initial imaging of choice in 44.7% and CT/CTA in 42.6%.

CONCLUSIONS

Imaging utilization in BPPV patients presenting with VDS is high. The profile of patients with BPPV that received imaging was substantially more benign than that of stroke patients (a quarter had no neurologic symptoms, exam findings, or stroke RFs). The HINTS exam was underutilized, and computed tomography was heavily utilized despite well-established limitations in diagnosing posterior circulation strokes. This study highlights the need for increased training in the HINTS exam, narrowing of the scope for computed tomography, and a higher threshold for imaging patients with isolated VDS.

(Doctor…My child keeps falling over) unexpected MRI findings in children with history of frequent falls and dizziness: a case series

Frequent falls and dizziness are common complaints in children. These symptoms can be caused by wide range of underlying pathologies including peripheral vestibular deficits, cardiac disease, central lesions, motor skills delay and psychogenic disorders. We report three paediatric cases who presented with complaints of repeated falls and imbalance. MRI scan revealed underlying brain lesions (frontal lobe arteriovenous malformation, exophytic brain stem glioma and cerebellomedullary angle arachnoid cyst with cerebellar tonsillar ectopia). By reporting these cases, we would like to emphasise the importance of a thorough assessment of children with similar symptoms by detailed clinical history, physical examination and maintaining low threshold for investigations, including radiological imaging. Taking in consideration, the wide range of differential diagnosis, the challenge of obtaining detailed history and difficulty of performing reliable physical examination in this age group. Management of underlying disorders can be medical, surgical or just observational.

Accelerated Time-of-Flight Magnetic Resonance Angiography with Sparse Undersampling and Iterative Reconstruction for the Evaluation of Intracranial Arteries

OBJECTIVE

To compare the image quality of three-dimensional time-of-flight (TOF) magnetic resonance angiography (MRA) with sparse undersampling and iterative reconstruction (sparse TOF) with that of conventional TOF MRA.

MATERIALS AND METHODS

This study included 56 patients who had undergone sparse TOF MRA for intracranial artery evaluation on a 3T MR scanner. Conventional TOF MRA scans were also acquired from 29 patients with matched acquisition times and another 27 patients with matched scanning parameters. The image quality was scored using a five-point scale based on the delineation of arterial vessel segments, artifacts, overall vessel visualization, and overall image quality by two radiologists independently, and the data were analyzed using the non-parametric Wilcoxon signed-rank test. Contrast ratios (CRs) of vessels were compared using the paired t test. Interobserver agreement was calculated using the kappa test.

RESULTS

Compared with conventional TOF at the same spatial resolution, sparse TOF with an acceleration factor of 3.5 could reduce acquisition time by 40% and showed comparable image quality. In addition, when compared with conventional TOF with the same acquisition time, sparse TOF with an acceleration factor of 5 could also achieve higher spatial resolution, better delineation of vessel segments, fewer artifacts, higher image quality, and a higher CR (p < 0.05). Good-to-excellent interobserver agreement (κ: 0.65-1.00) was obtained between the two radiologists.

CONCLUSION

Compared with conventional TOF, sparse TOF can achieve equivalent image quality in a reduced duration. Furthermore, using the same acquisition time, sparse TOF could improve the delineation of vessels and decrease image artifacts.

Post-Traumatic Dizziness: Clinical and Medicolegal Aspects

Subjective complaints of dizziness after mild-to-moderate traumatic brain injury are common. Alterations in the mode of injury have changed the presentation symptoms. Evolutions in neuroimaging challenge conventional concepts regarding lack of evidence of injury following mild head trauma and provide hope for elucidating the site of lesion in patients with post-traumatic balance symptoms. Yet the vestibular clinician must maintain a healthy level of suspicion regarding potential exaggeration of symptoms and disability in patients with a financial incentive. Unique conditions warrant particular attention by the vestibular clinician, including chronic traumatic encephalopathy, catastrophization, and persistent postural and perceptual dizziness. The clinical significance of abnormalities, particularly on vestibular-evoked myogenic potential testing, needs to be better defined prior to their widespread application in the medical legal arena. The role of the medical expert is to provide opinion on matters requiring special knowledge to assist the court in reaching its findings. As such, this chapter provides an update on recent advances to consider in patients with dizziness after trauma.

Early MRI-negative posterior circulation stroke presenting as acute dizziness

The aim of this study was to determine the frequency, clinical and radiological features, and efficacy of clinical evaluation and perfusion-weighted imaging (PWI) for the prediction of final stroke in patients with DWI/MRI-negative posterior circulation stroke (PCS) presenting acute dizziness/vertigo. From our comprehensive prospective stroke registry of acute ischemic stroke during a 7-year period, we identified 1846 consecutive patients with PCS, 850 of whom presented with acute dizziness/vertigo. Of these 850 patients, initial DWI-MRI was negative in 35 (4.1%). In these 35 patients, dizziness/vertigo was acute prolonged in 31 and recurrent transient in 4. Focal neurological signs or profound imbalance were present in 16/35 or 18/34, respectively. Spontaneous nystagmus was absent in 21/35; the HINTS protocol (head impulse, nystagmus, and test-of-skew) was not applicable to them. In 12/26 patients, PWI was positive and the same time as DWI was negative. The usual site of lesion was the lateral medulla (n = 18). Twenty-nine patients (83%) had small strokes, while 19 (54%) had large vessel strokes. The sensitivity of systematic clinical evaluation adopting neurological examination, HINTS plus, and assessment of equilibrium was 83%, for prediction of final stroke and 100% when combined with PWI. An integrated approach using systematic neurological and neuro-otological examinations combined with PWI accurately diagnoses PCS presenting with acute dizziness/vertigo. Although most patients with acute vertigo and MRI-negative PCS have small brainstem strokes, about a half have large vessel stroke with greater risk of progression requiring prompt treatment.

Gabapentin dose and the 30-day risk of altered mental status in older adults: A retrospective population-based study

Gabapentin is an effective treatment for chronic neuropathic pain but may cause dizziness, drowsiness, and confusion in some older adults. The goal of this study was to assess the association between gabapentin dosing and adverse outcomes by obtaining estimates of the 30-day risk of hospitalization with altered mental status and mortality in older adults (mean age 76 years) in Ontario, Canada initiated on high dose (>600 mg/day; n = 34,159) compared to low dose (≤600 mg/day; n = 76,025) oral gabapentin in routine outpatient care. A population-based, retrospective cohort study assessing new gabapentin use between 2002 to 2014 was conducted. The primary outcome was 30-day hospitalization with an urgent head computed tomography (CT) scan in the absence of evidence of stroke (a proxy for altered mental status). The secondary outcome was 30-day all-cause mortality. The baseline characteristics measured in the two dose groups were similar. Initiation of a high versus low dose of gabapentin was associated with a higher risk of hospitalization with head CT scan (1.27% vs. 1.06%, absolute risk difference 0.21%, adjusted relative risk 1.29 [95% CI 1.14 to 1.46], number needed to treat 477) but not a statistically significant higher risk of mortality (1.25% vs. 1.16%, absolute risk difference of 0.09%, adjusted relative risk of 1.01 [95% CI 0.89 to 1.14]). Overall, the risk of being hospitalized with altered mental status after initiating gabapentin remains low, but may be reduced through the judicious use of gabapentin, use of the lowest dose to control pain, and vigilance for early signs of altered mental status.

Brain responses to virtual reality visual motion stimulation are affected by neurotic personality traits in patients with persistent postural-perceptual dizziness

OBJECTIVE

Persistent postural perceptual dizziness (PPPD) is a common vestibular disorder of persistent dizziness and unsteadiness, exacerbated by upright posture, self-motion, and exposure to complex or moving visual stimuli. Previous functional magnetic resonance imaging (fMRI) studies found dysfunctional activity in the visual-vestibular cortices in patients with PPPD. Clinical studies showed that the anxiety-related personality traits of neuroticism and introversion may predispose individuals to PPPD. However, the effects of these traits on brain function in patients with PPPD versus healthy controls (HCs) have not been studied.

METHODS

To investigate potential differential effects of neuroticism and introversion on functioning of their visuo-vestibular networks, 15 patients with PPPD and 15 HCs matched for demographics and motion sickness susceptibility underwent fMRI during virtual reality simulation of a rollercoaster ride in vertical and horizontal directions.

RESULTS

Neuroticism positively correlated with activity in the inferior frontal gyrus (IFg), and enhanced connectivity between the IFg and occipital regions in patients with PPPD relative to HCs during vertical versus horizontal motion comparison.

CONCLUSIONS

In patients with PPPD, neuroticism increased the activity and connectivity of neural networks that mediate attention to visual motion cues during vertical motion. This mechanism may mediate visual control of balance in neurotic patients with PPPD.

Lateral medullary infarction with similar features of Brown Sequard syndrome caused by vertebrobasilar dysplasia and Klippel-Feil syndrome: A case report

RATIONALE

Patients with Klippel-Feil syndrome (KFS) are always anomaly associated with vertebrobasilar dysplasia. That may present commonly as infarction of brainstem, medulla, and cerebellum. In this article, we reported a rare case of lateral medullary infarction (LMI) with similar features of Brown Sequard syndrome caused by vertebrobasilar dysplasia and KFS, and the 2 rare conditions that are causally related. The case is being reported because of its unusual and rare presentation.

PATIENT CONCERNS

A 38-year-old female presented with acute unsteadiness, along with a tendency to lean to the left side while walking or sitting, and paresthesia in the right lower limb and trunk, at 2 days before admission. She had no history of hypertension and diabetes, but had a 20 years history of neck pain and dizziness, which was related to head movement.

DIAGNOSES

Brown Sequard syndrome and a lesion of the left thoracic spinal cord were suspected initially. KFS was confirmed by the cervical magnetic resonance imaging (MRI) and computed tomographic angiography (CTA) results. Transcranial Doppler (TCD) results confirmed that there was a causal link between LMI and KFS.

INTERVENTIONS

The patient rejected the operation of stabilization of the cervical spine with fusion at appropriate levels.

OUTCOMES

No recurrence of stroke, but neck pain and dizziness remained after 6 months of discharge.

LESSONS

For such patients, the conventional treatment of cerebral infarction might be ineffective, but stabilization of the cervical spine with fusion at appropriate levels can successfully prevent further episodes of syncope and stroke.

Test-Retest Reliability of Measuring the Vertebral Arterial Blood Flow Velocity in People With Cervicogenic Dizziness

OBJECTIVES

The purpose of this study was to determine the within-session and between-sessions reliability of measuring the vertebral artery blood flow velocities in people with cervicogenic dizziness using Doppler ultrasound at both upper and lower cervical levels.

METHODS

Outcome measures were taken on 2 occasions 3 weeks apart with no active treatment provided in between the assessments on 12 participants. Pulsed-wave Doppler ultrasound was used to quantify time-averaged mean velocities through the vertebral artery at upper cervical (C0-1) and lower cervical vertebrae (C5-6). The clinical outcome measures were also recorded in people with cervicogenic dizziness. The intraclass correlation coefficient (ICC) was used to determine the within-session and between-session repeatability. Paired t test was used to determine the differences in the time-averaged mean velocities of blood flow at the same site of the vertebral artery and the clinical outcome measures in 2 sessions 3 weeks apart.

RESULTS

In people with cervicogenic dizziness, there was no significant change in both clinical outcome measures and the time-averaged mean velocities when the patients were measured 3 weeks apart (P > .05). This study identified good within-session (ICC: 0.903-0.967) and between-session (ICC: 0.922-0.984) repeatability in measuring the vertical blood flow velocities in patients with cervicogenic dizziness when the clinical outcome measures were unchanged.

CONCLUSIONS

This study supports the use of Doppler ultrasound to identify changes in mean vertebral arterial blood flow velocities before and after intervention in people with cervicogenic dizziness in future studies.

The advantage of ultrasonography in the diagnosis of extracranial vertebral artery dissection: Two case reports

RATIONALE

With the rapid development in technology of vascular imaging, the detection of artery dissection is also gradually increasing. Cervical artery dissection, including carotid artery and vertebral artery dissection, is associated in at least 20% of young adult patients with stroke. So, the diagnosis of cervical artery has become a great challenge.

PATIENT CONCERNS

We reported 2 patients who complained of dizziness and pain, the findings of US confirmed the presence of extracranial vertebral artery dissection.

DIAGNOSES

The floating membrane in lumen and intramural hematoma were found in US, consistent with vertebral artery dissection, whereas DSA revealed no typical sign of artery dissection.

INTERVENTIONS

In order to the definite diagnosis we persuaded the patients to undergo DSA, but there was no strong evidence on the diagnosis of vertebtal artery dissection.

OUTCOMES

The patients were diagnosed of vertebral artery dissection by US.

LESSONS

US show more advantages in diagnosis of extracranial vertebral artery dissection, might even be considered as the first choice.

Auriculo-vestibular symptoms related to structural and functional disorders of stomatognatic system

Auriculo-vestibular symptoms are otolaryngological complaints which frequently co-occur with functional disorders of masticatory organ. These symptoms include: earache, plugged ears sensation, sudden hearing impairment, burning pain of the throat, tinnitus, and dizziness. The aim of the study was assessment of co-occurrence of functional disorders of masticatory organ and auriculo-vestibular symptoms, in patients referred for otolaryngological treatment. Forty-two patients aged 24-46 years of both sexes referred for otolaryngological treatment, because of auriculo-vestibular symptoms, were qualified to our study within the framework of research project. After otolaryngological diagnostics (Department of Otolaryngology), these patients were referred for prosthetic consultation to the Department of Dental Prosthetics of Jagiellonian University Medical College. In Otolaryngology Clinic the following specialist examinations were carried out: basic clinical examinations, including otoscopy, tuning fork trials, tonal and verbal audiometry, and tympanometry. These examinations were supplemented with electronystagmometry. On prosthetic consultation, specialist functional investigations of masticatory organ, and electromyographic assessment of the activity of masseter muscles and the anterior part of the temporal muscle, were carried out. Results of the investigation revealed otolarygological causes of the reported symptoms in 30 patients, whereas in 12 patients (out of 42 patients referred for prosthetic consultation), numerous functional disorders of the stomatognathic system were observed. The investigation confirmed the occurrence of functional disorders in patients with auriculo-vestibular symptoms and appropriateness of treatment by a multi-specialist team.

WISE-2005: developing a non-invasive method to monitor cardiovascular deconditioning

We have determined the gain of the cardiopulmonary baroreflex (CPBR) by measuring the central venous pressure (CVP) by venous catheter and calculating the total peripheral resistance (TPR) from mean arterial pressure (MAP) by Finometer and cardiac output (QD) by Doppler ultrasound. We tested the hypothesis that the BeatScope software of the Finometer, which calculates cardiac stroke volume (SVF) and cardiac output (QF) from the arterial pulse wave, could provide data with which to estimate CVP and TPR. The estimate of QF was linearly related to QD with a correction factor. Further, we found linear relationships between CVP and SVF that allowed us to establish a prediction of CVP from the SVF as the new input to the CPBR. To test the ability of this method to monitor changes in CPBR we are testing the subjects of the WISE-2005 study before and after 50-days of bed rest. We conclude that the TPR can be assessed with the Finometer and without any invasive method to record the CVP.

WISE-2005: reduced cerebral blood flow velocity with nitroglycerin--comparison with common carotid artery blood flow

During the WISE-2005 study of 24 women, we observed a reduction (21.6 +/- 0.89%, mean +/- SEM) in cerebral blood flow velocity (CBV) measured by transcranial Doppler ultrasound, following 0.3 mg sublingual nitroglycerin (NG). In parallel, we observed quantitative reductions in leg blood flow (47.3 +/- 7.0%) and corresponding reductions in calculated conductance (Conductance = Femoral Flow / Mean Arterial Pressure; 45.7 +/- 7.2%). To determine if the reduction in CBV was the result of reduced cerebral blood flow or dilation of the middle cerebral artery (MCA), the change in CBV in the MCA was compared with changes in quantitative flow measured in the common carotid artery (CCA). The relationship between CBV and CCA blood flow was tested in five men and four women using hyper- and hypo-ventilation to manipulate arterial PCO2. Changes in CCA blood flow were positively correlated with changes in CBV (p<0.001). We then investigated the CBV and CCA flow responses to sublingual NG in an additional two men and six women. Concurrent with the reduction in CBV there was no change in blood flow through the CCA (p>0.05). These results indicate that the decrease in CBV observed in response to NG was probably the result of dilation of the MCA and that total cerebral blood flow was similar after administration of NG. These results suggest regional differences in the vascular responses to NG during the WISE bed rest. Conduit vessels of both the peripheral and cerebral vasculature dilated; however, the resistance vessels in skeletal muscle constricted causing a reduction in blood flow, while the resistance vessels of the brain appeared to be unaffected by NG so that cerebral blood flow remained constant. These results highlight the need to obtain quantitative measures of cerebral blood flow if there is reason to suspect that the diameter of the MCA might not remain constant.

Tibial and gastrocnemian vein response to LBNP after a 60 day bedrest with and without counter-measures (WISE study)

The objective was to quantify calf vein cross section area (CSA) maximal enlargement and the percent change in response to LBNP (lower body negative pressure) after a 60 day bedrest.

METHOD

The 24 healthy volunteers (25-40 y) of the WISE 60 day HDT(-6 degree) bedrest, were divided into 3 groups: Control (Co), Exercise countermeasure (Ex: treadmill under LBNP and flywheel), Nutrition (Nut: daily protein supplement). All were studied at -45mmHg LBNP pre and at HDT day 55. Posterior Tibial (Tib), and Gastrocnemian (Gast) vein were investigated by echography using an echographic probe fixed at the upper and posterior part of the calf. From the post HDT CSE test the subjects were identified as finisher or non finisher to the 10-min tilt tolerance test.

RESULTS

At LBNP-45mmHg, the maximal enlargement of the Tib and Gast veins remained constant pre, and at HDT day 55 in all group (Co, Ex, Nut, finisher, non finisher). For both veins there was a higher vein distension (percent change from supine rest to -45mmHg) in Co and Nut group compared to Ex group despite the maximal distension was similar in all groups. Also the vein distension was higher in non finisher than in finisher.

CONCLUSION

The maximal distension of the vein were not affected nor by HDT nor by CM. The Ex counter-measure minimized the bed rest effect on leg vein distensibility (percent CSA change) while the Nut countermeasure had no effect. Higher leg vein distensibility was associated with reduced orthostatic tolerance.

Effect of the elastic compression stockings on the calf veins and tissues during a simulated orthostatic test (LBNP)

The objective of the present study was to quantify the effects of elastic compression stockings (ECS) on the leg hemodynamics, the venous return (flow and distensibility) and on the leg superficial tissue thickness.

MATERIAL & METHODS

10 healthy women were submitted to LBNP (Lower Body Negative Pressure) tests without then with ECS (French pressure class 1, 2 and 3). The subject was instrumented with Doppler and echographic probes for assessing the femoral artery, the external saphenous and the gastrocnemian vein.

RESULTS

1) At -40 mmHg the heart rate and blood pressure didn't change significantly with or without ECS. 2) The lower limb vascular resistance increased by 20 to 25% (p<0.01) from the initial values (i.e. without depressure) without or with class 1 or 2 ECS, while it increased less (13%, p<0.01) with class 3 ECS. 3) With ECS, the gastrocnemian vein area was reduced by 10 to 15% (p<0.01) from the initial values, in proportion to the ECS class. 4) The maximal distension (cross section) of this vein at -40 mmHg remained similar with or without ECS, but the percent change in vein distension was significantly higher with ECS than without. 5) Only without ECS, the distance between the external saphenous vein and the skin increased by 13% at -40 mmHg (p<0.01) from the initial values (increase of the calf peripheral area by 11% p<0.01). With ECS, there was no increase in distance nor area during LBNP.

CONCLUSION

ECS had no effect on the main arterial hemodynamics and venous cross section area, while it prevented liquid stowage into the superficial tissue.

Applications of the marchbanks transcranial-cerebral sonography technique in neurootology: preliminary report

Transcranial-cerebral sonography (TCCS) is a noninvasive technique that allows clinicians to detect nanoliter (billionths of a liter) displacements of the tympanic membrane. This technique was developed to assess cerebrospinal fluid (CSF) pressure in cases of shunted hydrocephalus; it takes advantage of the CSF connection to the inner ear through the cochlear aqueduct. The movements of the tympanic membrane that are observed in TCCS are those evoked by the acoustic stapedius reflex and those spontaneous movements generated by intracranial arterial, venous, and respiratory pulses transmitted through the inner ear to the stapes and thence to the tympanic membrane. Analysis of the amplitude and direction of these displacements has enabled neurosurgeons and neurologists to estimate CSF pressures accurately in patients evaluated by TCCS. TCCS allows for applications in neurootology, particularly in those patients who present with symptoms of pulsating tinnitus, dizziness and imbalance, or hearing loss. This preliminary report describes the test and its application in a series of patients whose diagnoses included pulsating tinnitus, idiopathic intracranial hypertension, Ménière's disease, perilymphatic fistula, perilymphatic hypertension, arterial stenosis, and Arnold-Chiari syndrome. We conclude that TCCS is a valuable addition to the armamentarium of neurootologists.

Transcranial Doppler sonography in children: review of a seven-year experience

AIM

We report the use of transcranial Doppler sonography (TCD) examinations in children (mean age 12.7 years; range 0.5-18 years) without an open fontanelle, using TCD equipment with a 2 MHz pulse wave transducer. Our results over a 7-year period are described.

MATERIAL AND METHODS

A total of 858 children were referred from the paediatric outpatient department. All patients were divided into three groups according to the reason for referral.

RESULTS

We found positive pathological results in the following: (1) headache and orthostatic dysregulation (0.4%, three out of 728); (2) acute neurological symptoms (5.4%, six out of 112); (3) other indications (22.2%, four out of 18). The positive predictive value of finding an abnormality was very low (0.50).

CONCLUSION

TCD examination is ineffective in children with non-specific headache or orthostatic dysregulation due to the specific limitations of this method. We found a higher percentage of abnormal results in children referred for other indications. However, since these children usually undergo MR imaging (and MR angiography, if necessary), in our opinion the TCD examination does not add any additional information. The value of TCD in children is not in the primary diagnosis of disease but in the follow up of known vascular processes (e.g. stenoses) or in chronic diseases including angiitis and sickle cell disease.

The use of a two-dimensional ultrasound time-of-flight system for location of the centre of gravity in posturography measurements

A method has been developed for objective assessment of balance using ultrasound time-of-flight (ToF) posturography measurements to accurately locate the centre of gravity (CoG) of a subject. Two orthogonal 40 kHz ultrasound transmitters are mounted on the subject's waist at the height of the CoG. Anterior/posterior and lateral motions are detected independently by measuring variations in the ToF from the transmitters to appropriately positioned wall-mounted receivers. The motion of the CoG is accurately traced during the course of 20 second assessment periods as the subject stands on a solid surface with eyes open and eyes closed. The tests are repeated with the subject standing on a standardized soft surface. Trials of day-to-day repeatability and repeated tests on patients prior to therapy indicate there is no significant improvement to balance measures with experience of the system. Balance measures are significantly worse in patients suffering vertigo symptoms following traumatic brain injury than for equivalent normal volunteers. Repeated measures post-therapy indicate significant improvement in balance measures following vestibular therapy in patients with vertigo. CoG location using ultrasound ToF is a suitable method of tracking sway and thus assessing balance in normals and balance-compromised patients.

Validation of CBF measurement with non-invasive microsphere method (NIMS) compared with autoradiography method (ARG)

The purpose of this study is to examine the correlation of measured regional cerebral blood flow (rCBF) by means of a new microsphere method (non-invasive microsphere method), to the autoradiography (ARG) method, which is an established quantification method for 123I-IMP brain SPECT. The non-invasive microsphere (NIMS) method and ARG method were simultaneously applied to 30 patients, and quantified rCBF maps were calculated with each method. A significant correlation (r = 0.70: p < 0.001) was detected between mCBF values calculated with the NIMS and ARG methods. This new method seems to reliably quantify rCBF with brain SPECT.

SPECT brain perfusion abnormalities in mild or moderate traumatic brain injury

The purpose of this atlas is to present a review of the literature showing the advantages of SPECT brain perfusion imaging (BPI) in mild or moderate traumatic brain injury (TBI) over other morphologic imaging modalities such as x-ray CT or MRI. The authors also present the technical recommendations for SPECT brain perfusion currently practiced at their center. For the radiopharmaceutical of choice, a comparison between early and delayed images using Tc-99m HMPAO and Tc-99m ECD showed that Tc-99m HMPAO is more stable in the brain with no washout over time. Therefore, the authors feel that Tc-99m HMPAO is preferable to Tc-99m ECD. Recommendations regarding standardizing intravenous injection, the acquisition, processing parameters, and interpretation of scans using a ten grade color scale, and use of the cerebellum as the reference organ are presented. SPECT images of 228 patients (age range, 11 to 88; mean, 40.8 years) with mild or moderate TBI and no significant medical history that interfered with the results of the SPECT BP were reviewed. The etiology of the trauma was in the following order of frequency: motor vehicle accidents (45%) followed by blow to the head (36%) and a fall (19%). Frequency of the symptoms was headache (60.9%), memory problems (27.6%), dizziness (26.7%), and sleep disorders (8.7%). Comparison between patients imaged early (<3 months) versus those imaged delayed (>3 months) from the time of the accident, showed that early imaging detected more lesions (4.2 abnormal lesions per study compared to 2.7 in those imaged more than 3 months after the accident). Of 41 patients who had mild traumatic injury without loss of consciousness and had normal CT, 28 studies were abnormal. Focal areas of hypoperfusion were seen in 77% (176 patients, 612 lesions) of the group of 228 patients. The sites of abnormalities were in the following order: basal ganglia and thalami, 55.2%, frontal lobes, 23.8%, temporal lobes, 13%, parietal, 3.7%, insular and occipital lobes together, 4.6%.

The appropriate use of the duplex scan in carotid arterial disease

The duplex scan has become the definitive test in the diagnosis of carotid arterial disease. Its significance, however, has been diminished its extensive use for inappropriate indications. We performed a retrospective study over a four year period at two major hospitals to evaluate the different indications for carotid duplex scans. Symptoms which prompted the test, associated diseases, the type of physician ordering the test, and demographic data were recorded on all patients. Statistical analysis was used to indicate which symptoms and associated diseases were significant in predicting carotid disease. A total of 4,764 scans were reviewed. There were 4,289 studies (90%) which were negative for disease requiring surgery. There were a total of 12 indications for the carotid duplex scan in this study; the most common indications were dizziness, (20%) transient ischemic attack symptoms (19%) and a bruit (16%). Vascular surgeons (28%), Internal Medicine physicians (27%) and Family practice physicians (15%) ordered the duplex scan most frequently, but 39% of the positive scans were ordered by vascular surgeons. A history of seizures, confusion, stroke and as a preoperative evaluation all had a very low yield and should not be used as an indication for a duplex scan. However, a long smoking history, a history of known carotid disease, and peripheral vascular disease all had a statistical correlation with an abnormal duplex scan. The use of the duplex scan to rule out carotid arterial disease for patients with vague, uncommon symptoms is inappropriate and wasteful.

Single-photon-emission computed tomography (SPECT) in neurotologic assessment: a preliminary report

The single-photon-emission computed tomography (SPECT) scan enables clinicians to probe dynamic and metabolic changes in brain tissue through measurement of regional cerebral blood flow (rCBF). Diagnostic benefits of the SPECT scan in clinical neurology have been demonstrated. SPECT scanning has been shown to be more sensitive than morphologic imaging techniques [magnetic resonance imaging (MRI) and computed tomography (CT)] in many conditions. However, the use of the scan in assessing neurotologic complaints remains inadequately investigated. Few studies have explored the value of SPECT in establishing the causes of dizziness, hearing loss, and tinnitus. We studied SPECT along with MRI, CT scan, electroencephalogram (EEG), and other evaluations in patients with these neurotologic complaints, SPECT abnormalities were more frequent and prominent than those visualized by other imaging modalities. Overall, 78% of SPECT scans revealed abnormalities. Abnormalities were found in 46% of MRIs, 40% of CTs, and 29% of EEGs. The disparity between SPECT scanning and other procedures was also seen once patients were divided by their chief complaints. This study illustrates the sensitivity of SPECT scanning in evaluating neurotologic complaints and highlights the need for additional research into the importance of SPECT scanning in comprehensive neurotologic evaluation.

Neuroradiology of vestibular pathways

Comprehensive efficacious neuroimaging of the vestibular pathways requires cooperation and coordinated efforts between the otologist and the neuroradiologist to avoid duplication of expensive and sometimes invasive study. For peripheral lesions, for example, those of the labyrinthine organ, thin-section CT is optimum as a first examination. For retrolabyrinthine lesions along nerve tracts or in the central pathway, MRI is preferred. When bone erosion occurs, CT can also be helpful in evaluation of the base of the skull to detect and define the extent of these lesions, for example, cholesterol granuloma and glomus tumor.

[Preliminary study of patients with vertigo and dizziness using 123I-IMP]

To study the application of cerebral blood flow scintigraphy with 123I-IMP for the evaluation of central dizziness, the difference in 123I-IMP accumulation between the right and left cerebellar hemispheres was determined as an asymmetry index (A.I.) in 8 normal subjects and compared with A.I. from patients with central dizziness. According to estimated lesions, 123I-IMP findings were compared with CT findings. The normal subjects had A.I. of 5.8 +/- 2.1%, whereas 36 patients with central dizziness had A.I. of 12.7 +/- 7.5%. On the basis of an A.I. of 8% or more as an abnormal finding on IMP scintigraphy, 11 of the 14 patients with estimated lesions of cerebellar hemispheres and 16 of the 20 with those of the whole cerebellum including the vermis were evaluated to have had abnormalities. Seven of 11 with estimated lesions of the brainstem and 4 of 5 with vertebrobasilar arterial insufficiency were evaluated to have had abnormalities. The findings of 123I-IMP cerebral blood flow scintigraphy were in good agreement with clinical symptoms in patients with central dizziness with estimated lesions of the cerebellar hemispheres, suggesting the possibility that this method is more useful than CT.

The value of CT and very low field MRI in the etiological diagnosis of dizziness

A total of 79 dizziness patients were examined by either computed tomography (CT), or very low field magnetic resonance imaging (MRI), or both. In most cases, the patients were selected for the neuroimaging because preliminary clinical examination had suggested central nervous system (CNS) involvement. Abnormal CT or MRI findings with probable clinical relevance to the etiology of dizziness were obtained in 34%. The most common abnormalities were atrophy, infarction, and demyelination.; 29% of the CT scans and 40% of the MRI showed relevant abnormalities. The present results emphasize the diagnostic usefulness of head CT and MRI when dizziness of CNS etiology is suspected.

Evaluation of the dizzy patient

The differential diagnosis of dizziness is difficult, yet challenging. There continues to be a need for improvement in assessment and evaluative procedures for patients with symptoms of dizziness. The otologist must exclude a wide variety of potential disorders which could be sources of the symptoms. The key to a well-made differential diagnosis is a very carefully taken, thorough, medical history, and the integration of that history with the physical examination, the audiometry, and the vestibular evaluation.